The impact of different cervical planning target volume designs on efficacy and toxicity in nasopharyngeal carcinoma: a single-center retrospective study.

BACKGROUND

In nasopharyngeal carcinoma (NPC) patients, two radiation target delineation patterns are used for the cervical lymph node area.

PURPOSE

This study compares the efficacy and toxicity of two radiation target volume delineation patterns for planning target volumes (PTVs) in NPC patients.

METHODS

This retrospective analysis included 387 non-metastatic NPC patients treated with concurrent chemoradiotherapy from January 2017 to December 2020. Patients were divided into two groups: the 2-PTV group with two dose gradients (50-54 Gy and 66-70 Gy) and the 3-PTV group with an additional 60-63 Gy dose.

RESULTS

After a median follow-up of 51.2 months, the 3-year regional relapse-free survival (RRFS) showed no significant differences between the 3-PTV and 2-PTV groups (96.6% [95% confidence interval (CI): 96.5%-96.8%] and 96.3% [95% CI: 96.2%-96.3%]). In the N3 subgroup, the 3-year RRFS was also comparable between the 3-PTV and 2-PTV groups (96.2% [95% CI: 76%-99%] vs. 95% [95% CI: 69%-99%], p = 0.727). Importantly, the 2-PTV group demonstrated significantly lower rates of grade 3/4 dermatitis (5.1% vs. 16.5%; HR 0.88, 95% CI: 0.82-0.94, p = 0.002) and xerostomia (49.6% vs. 67%; HR 0.78, 95% CI: 0.72-0.84, p = 0.002).

CONCLUSIONS

The 2-PTV regimen achieved equivalent survival outcomes while significantly reducing treatment-related toxicities compared to the 3-PTV approach. These results suggest that the 2-PTV strategy may offer a more favorable therapeutic profile for NPC patients, particularly in minimizing severe dermatitis and xerostomia.